Process for regulating flow of contact material



July 23, 1963 H. R. DAILY 3,098,815

PROCCESS FOR REGULATING FLOW OF CONTACT MATERIAL Original Filed March21, 1957 Hg. I 34 ll IN V EN TOR. HOWARD R. DAILY mma. 5 M

TORNEY fii i fi ls Patented July 23, 1963 3,098,815 PRGGESS FURREGULATENG FLOW 9F QGNTAQT MATERlAL Howard R. Daily, Toledo, Ulric,assignor to Sun Oil Company, Philadelphia, Pa, a corporation of NewJersey Original application Mar. 21, 1957, Ser. No. 647,534, new PatentNo. 3,011,662, dated Dec. 5, 1961. Divided and this application .iune3t), 1959, Ser. No. 824,056 3 (Ilaims. (ill. 208-167) This inventionrelates to process and apparatus for regulating the flow of granularsolid contact material through a contacting vessel, for example areaction vessel for use in promoting reactions by contact with granularsolid contact material.

In the art of conversion of petroleum hydrocarbons by contact withgranular solid contact material capable of promoting or catalyzingconversion of hydrocarbons, e.g. decomposition of high molecular weightpetroleum materials to lower molecular weight products, it is known togravitate the contact material through a portion of the reaction zone asa compact bed. It is also known to supply contact material to the uppersurface of the bed as a falling stream of contact material, the liquidhydrocarbon reactants being sprayed into contact with the granularsolids in the falling stream. It is often desirable to employ aplurality of such falling streams in parallel, spaced apart over thehorizontal cross section of the reaction vessel. This construction isdesirable in order to provide more nearly uniform level of the uppersurface of the compact bed.

However, it frequently happens that the rate of flow of contact materialin the various falling streams is not uniform, with the result that thesurface of the compact bed will be lower in some parts than in others.This is an undesirable circumstance, since it tends to result in uneventemperature distribution in the reactor, poor efficiency in the crackingor other operation, and other disadvantages. The present inventionprovides a novel process and apparatus whereby these disadvantages canbe avoided, and more nearly uniform level of the upper surface of thecompact bed obtained.

The invention will be further described with reference to the attacheddrawing, wherein FIGURE 1 is a sectional elevational view of oneembodiment of apparatus according to the invention, and FIGURE 2 is asectional plan view of the same apparatus.

Referring to the drawing, reaction vessel has an upper inlet 11 forgranular solid contact material and a lower outlet 12 for granular solidcontact material. Also associated with vessel 10 are four inlet conduitsl3, 14, 15 and '16 ior liquid hydrocarbon cracking charge. Transversepartition 17 within vessel 10 provides an upper chamber thereabovethrough which contact material introduced through line dd gravitates asa compact mass into the tour conduits d8, 19, 20 and 21 which dependfrom partition 17. Surrounding the conduits '18 to 21 are four sleeves22, 23, 24 and 25 having closures at the lower end thereof. Each closuremember contains an annular aperture, two of which are indicated at 26and 27. At the lower end of the hydrocarbon inlet conduits 13, 14, 15and 16 are spray nozzles, two of which are indicated by the numerals 28and 29, adapted to discharge atomized liquid hydrocarbon cracking chargeinto the tour tailing streams of contact material, three of which arerepresented by the numerals 30, 31 and 60.

The compact bed 52 of contact material, onto which the four fallingstreams are discharged can be considered to have four portions, three ofwhich are represented by the numerals 3'2, 33 and er, directly beneatheach of the four falling streams. A hollow shaft 34- has at the lowerend thereof a holder 35 for a radioactive material such as radium, thisholder being located centrally with regard to the four elevated portionsof the compact bed. Four Geiger counters 36, =37, 38 and '39 are spacedaround the outer wall of the vessel 10 at locations such that they areadapted to receive radiations transmitted, from the source ofpenetrative radiation within holder 35, through the correspondingportions of the compact bed. Associated with each counter is anindicator, two of which are represented by the numerals 53 and 54. Theseindicators can be of any suitable known construction, :for indicatingthe magnitude of the radiation received by the associated counter.

Four fluid conduits, two of which are represented by the numerals 44 and45, communicate with the sleeves 22 to 25 in order to permit theintroduction of an inert fluid such as steam into the annular spaces 48,49, 50 and 51 between the sleeve and the corresponding conduit forintroduction of contact material. Each fluid conduit 'has a valvetherein, two of which are represented by the numerals 46 and 47, forregulating the rate of flow of inert fluid through the conduit.

In operation, granular solid contact material is introduced through line1 1 into vessel 10, gravitates through the upper chamber as a compactbed, and then through the conduits 18, 19, 20 and 21 as compact masses.The contact material passes through the apertures 26, 27 and others andfalls therebeneath in the streams 30, 31 and others onto the uppersurface of the compact bed. The rate of flow of contact material throughthe apertures is proportional to the pressure of the inert fluid in thechambers '48 to 51. Thus, by increasing this pressure by increasing therate of introduction of inert fluid, the rate of flow of contactmaterial through the aperture is increased, and vice versa. This eifect,and suitable means for achieving it, are disclosed in United StatesPatent No. 2,7 26,938 issued December 13, 1955, to Raymond C. Lassiat.

Inert scaling medium is introduced by means not shown into the portionof the vessel above partition 17, and conventional means are provided tomaintain a suitable pressure differential between that portion and theportion of the vessel between the upper surface of bed 33 and partition17.

The heights of the various portions of the compact bed are subject tofluctuation in ordinary operation, this linetuation being attributableto diiferences in the rate of flow of contact material in the differentfalling streams. Thus for example, because of some unbalance in theoperation, the upper surface of portion 32 may rise. When this occurs,the amount of radiation transmitted from the radium in holder 35 throughthe elevated portion 32 de creases, because of the additional contactmaterial through which the radiations pass. At the same or a differenttime, the upper surface of portion 33 may fall for example, and theamount of radiation transmitted through the portion 33 to the counter 37increases when this occurs, because of the lesser amount of contactmaterial through which the radiations pass.

According to the present invention, upon a decrease in the amount ofradiation received by counter 36 for example, the opening of valve 46 isdecreased, with resulting decrease in pressure in zone '48. This resultsin a decrease in the rate of flow of contact material through aperture26 and restores the desired level of the portion 32. Similarly, upon anincrease in the amount of radiation received by counter '37 for example,the opening of valve 47 is increased, thereby to increase pressure inzone 43, increase the rate of flow of contact material through aperture27. and restore the desired level of portion 33.

In this manner, the level of the upper surface of the 3 compact bed ismaintained more nearly uniform, and the rates of flow of contactmaterial in the various falling streams are maintained substantiallyequal. This results in improved efiiciency in the cracking operation.

The operation has been described with reference to a process forconversion of hydrocarbon material by contact with granular solidcon-tact material. However, it is to be understood that the invention isadvantageously employed in any system where a plurality of horizontallyspaced apart falling streams of contact material are discharged onto theupper surface of a compact bed, the level of which it is desired tomaintain substantially constant.

It is further to be understood that the invention contemplates the useof any means for regulating the rate of flow of contact material in thevarious falling streams, in response to changes in the amount ofradiation transmitted through the spaces beneath the upper ends of therespective falling streams. The particular method described, involvingc'hanges in inert fluid pressure as a means of changing the rate of flowof contact material through an orifice, is preferred in that it avoidsthe use of moving parts within the vessel 10. However, it is to beunderstood that other means for regulating the flow of contact material,as well know in the art, e.g. slide valves or other types of valves inthe contact material conduits, can be employed. The present inventioncresides in separately regulating by any suitable means the rate of flowof con-tact material in each of a plurality of falling streams, inaccordance with the amount of radiation transmitted through the spacebeneath the upper end of each falling stream.

In the operation previously described, the radiations transmitted fromthe source pass through a portion of the compact bed of solids inordinary operation, and either a rise or a fall in the level of thecompact bed changes the amount of radiation transmitted. It is alsowithin the scope of the invention for the source and counter to bepositioned above the upper surface of the compact bed in ordinaryoperation, in which case only an increase in the level of the uppersurface of the compact bed changes the amount of radiation transmit-ted,whereupon the rate of flow of contact material in the particular fallingstream involved is reduced in order to lower the level until it is againbeneath the source and counter.

It is also within the scope of the invention to provide a plurality ofvertically spaced sources of penetrative radiation in the centralportion of the vessel. In stabilized operation, some of these sources,in one embodiment, can transmit radiations to the counter withoutpassing through any portion of the bed of contact material, whereasradiations from some of the lower sources pass through a portion of thebed before reaching the counter. An increase in bed level reduces theamount of radiations transmitted, and a decrease in bed level increasesthe amount transmitted. In the light of the present specification, aperson skilled in the art can determine the desired number and spacingof sources in this embodiment in accordance with the circumstances of agiven case.

According to the present invention, when the amount of radiationtransmitted through portion 32 for example decreases, this result isindicated by the indicator 5-3, whereupon the opening of valve 46 isdecreased in order to decrease the rate of introduction of inert fluidinto annular space 48. This results in a reduction in the rate of flowof contact material through orifice 26 and a consequent lowering \of thelevel of the upper surface of portion 32. The decrease in the opening ofvalve 46 can be performed manually or automatically within the scope ofthe invention. Thus, if desired, any suitable known means can beemployed for automatically changing the opening of valve 46 in responseto a change in the amount of radiation received by counter 36. Suchmeans are capable of decreasing the opening of valve 46 when the amountof radiation received falls below a predetermined level, and ofincreasing the opening of valve 46 when the amount of radiation receivedrises above that predetermined level. Means for automatically performingsuch changes in valve position are well known in the art, and anysuitable known means can be employed. It is also within the scope of theinvention for the change in the valve position to be performed manuallyby an operator after observing the change in reading of the indicator53. The same considerations apply with regard to the other valves andindicators.

The invention has been previously described with reference to a systemwherein four annular falling curtains of contact material are provided.It is to be understood that the invention is applicable to any systemcontaining two or more such falling curtains. Preferably, the fallingcurtains are spaced uniformly over the cross section of the vessel, inorder that contact material is distributed over substantially equalportions of the cross section from each falling curtain.

In the operation described previously in connection with the drawing thecounters such as counters 36 and 37 are positioned on substantially thesame horizontal level as a single source of penetrative radiation. It isalso within the scope of the invention to position the counters ondifferent horizontal levels from that of a single source, or to providea plurality of sources spaced over a vertical span which may or may notinclude the level of the counters. Any suitable arrangement can beemployed which will provide the desired result of providing a change inthe amount of radiation received when the level of the upper surface ofthe elevated portions of the compact bed changes.

The present invention is particularly advantageously applied tohydrocarbon conversion processes involving contact of liquid hydrocarbonmaterial with granular solid contact material. Cracking, coking,reforming, desulfurization processes, etc., are typical of the types ofconversion to which the present invention may be applied. A particularlybeneficial application of the invention is in hydrocarbon crackingprocesses. Typical operation in such process involves introducing heatedcontact material, at a temperature for example within the approximaterange from 800 F. to 1200 B, into a cracking zone, and introducinghydrocarbon charge into the cracking zone at a temperature within theapproximate range from 600 F. to 900 F. The contact material withdrawnfrom the cracking zone is introduced into a regeneration zone, whereinit is contacted with free-oxygen containing gas under conditionssuitable for oxidation of carbonaceous materials deposited on the solidsduring the cracking operation. It is then customary to elevate thesolids by suitable known means to a position above the cracking vessel,and gravitate the solids as a compact mass through the cracking vesselagain. Natural or activated clays, bauxite, activated alumina, syntheticsilica-alumina catalyst, etc., are examples of catalyst materialscommonly employed in hydrocarbon conversion processes. Zirkite, mullite,corhart, etc., are examples of refractory heat transfer materials whichcan be employed as conversion-supporting contact materials in suchprocesses. The particle size of the contact material employed in suchprocesses is generally within the approximate range from 3 to 20 mesh onthe United States Sieve Series scale.

-It is not necessary according to the invention that, in stabilizedoperation, the portions 32 and 33 and others should be dome-shaped asshown in the drawing. It is within the scope of the invention tomaintain by suitable means a substantially level upper surface instabilized operation. In this embodiment, a single source of penetrativeradiation can be employed, positioned slightly above the upper surfaceat the stabilized level. Alternatively, a plurality of sources can beemployed, with sources both above and below the upper surface at thestabilized level.

If desired, downcomers of suitable known construction and positioningcan be employed, spaced around the periphery of the vessel, to assist inmaintaining uniform bed level. Such downcomers are disclosed in numerouspatents, e.=g. United States Patent No. 2,683,109 issued July 6, 1954,to David E. Norris. Also, a clowncomer can be employed substantially onthe longitudinal axis of the vessel, in the position occupied by thelower portion of shaft 34 in the drawing.

The latter downcomer functions to avoid the presence of the depressedportion of the bed level at the center of the vessel. When suchdowncomer is employed, the radium source can be positioned at the wallof the downcomer. If desired, a plurality of sources can be employedspaced around the wall of the downcomer, though one source in generallysufficient.

Any suitable known material for providing penetrative radiation which isabsorbed more by the contact material than by the fluid medium in thecontacting vessel can be employed according to the invention. Byemploying a hollow shaft such as the shaft 34 in the drawing, the sourcecan be introduced and withdrawn Without affecting the rest of theapparatus or operation. However, any other suitable means ofposition-ing and supporting the source within the vessel can beemployed.

This application is a division of copending application Serial No.647,534 filed March 21, 1957, now Patent No. 3,011,662.

The invention claimed is:

1. Process for regulating flow of granular solid contact material whichcomprises: passing granular solid contact material through a portion ofthe height of an elongated contacting zone as a plurality ofhorizontally spaced apart falling streams, onto the upper surface of acompact, downwardly moving bed of contact material; transmittingpenetrative radiation from a central position relative to said fallingstreams laterally through each of the spaces directly beneath the upperends of said falling streams; detecting the amount of radiationtransmitted through each of the spaces, the amount being in inverserelationship to the height of the upper surface of the bed in theportion of the Zone through which the radiation passes; decreasing therate of fiow of contact material in a given falling stream in responseto a decrease in the amount of radiation transmitted through the spacebeneath the upper end of that falling stream; and increasing the rate offlow of contact material in a given falling stream in response to anincrease in the amount of radiation transmitted through the spacebeneath the upper end of that falling stream.

2. Process according to claim 1 wherein said decreasing is performed bydecreasing the pressure exerted on a body of contact material whilepassing through an orilice into the falling stream, and said increasingis performed by increasing the pressure exerted on said body whilepassing through said orifice.

3. Process according to claim 1 wherein said contact material is acracking catalyst, wherein liquid hydrocarbons are introduced at 600 to900 F. into contact with said falling streams of contact material at 800to 1200 F., and wherein the hydrocarbons are subjected to catalyticcracking by contact with the contact material.

References Cited in the file of this patent UNITED STATES PATENTS2,458,162 Hagerbaumer Ian. 4, 1949 2,613,326 Herzog Oct. 7, 19522,674,363 Graham Apr. 6, 1954 2,726,938 Lassiat Dec. 13, 1955 2,750,144Beckwith June 12, 1956 2,828,422 Steierman Mar. 25, 1958 OTHERREFERENCES Weighing Bagasse and Sugar With Gamma Rays, by Burr et al.,from Hawaiian Sugar Technologists, 1954.

1. PROCESS FOR REGULATING FLOW OF GRANULAR SOLID CONTACT MATERIAL WHICH COMPRISES: PASSING GRANULAR SOLID CONTACT MATERIAL THROUGH A PORTION OF THE HEIGHT OF AN ELONGATED CONTACTING ZONE AS A PLURALITY OF HORIZONTALLY SPACED APART FAFFILN STREAMS, ONTO THE UPPER SURFACE OF A COMPACT, DOWNWARDLY MOVING BED OF CONTACT MATERIAL; TRANSMITTING PENERATTIVE RADITION FROM A CENTRAL POSITION RELATIVE TO SAID FALLING STREAMS LATERALLY THROUGH EACH OF THE SPACED DIRECTLY BENEATH THE UPPER ENDS OF SAID FALLING STREAMS; DETECTING THE AMOUNT OF RADIATION TRANSMITTED THROUGH EACH OF THE SPACES, THE AMOUNT BEING IN INVERSE RELATIONSHIP TO THE HEIGHT OF THE UPPER SURFACE OF THE BED IN THE PORTION OF THE ZONE THROUGH WHICH THE RADIATION PASSES; DECREASING THE RATE OF FLOW OF CONTACT MATERIAL IN A GIVEN FALLING STREAM IN RESPONSE TO A DECREASE IN THE AMOUNT OF RADIATION TRANSMITTED THROUGH THE SPACE BENEATH THE UPPER END OF THAT FALLING STREAM; AND INCREASING THE RATE FLOW OF CONTTACT MATERIAL IN A GIVEN FALLING STREAM IN RESPONSE TO AN INCRREASE IN THE AMOUNT OF RADIATION TRANSMITTED THROUGH THE SPACE BENEATH THE UPPER END OF THE FALLING STREAM. 